[EM] Ultimate SPE Agenda Processing: Sink Swap Bubble

[Forest Simmons]

Suppose someone provides a list of candidates already sorted pairwise.

Now do Benham elimination ... start at the loser end of the list and
eliminate candidates one by one until there is (according to a fresh set of
ballots) a CW among the uneliminated.

How much incentive if any to rank insincerely?

On Mon, Apr 10, 2023, 12:50 AM Kevin Venzke <stepjak at yahoo.fr> wrote:

> Hi Forest and Kristofer,
>
> A couple of old responses. I know Forest has continued to post new ideas.
>
> Kristofer wrote:
> > This is about chicken resistance in general, no? I suspect there's a
> > more general impossibility result hiding here: that methods that are
> > burial resistant and Condorcet (in the way the Smith-IRV hybrids or
> > Friendly is) have to make uncharitable interpretations of ballots that,
> > if they were honest, would imply a very different candidate should be
> > elected. (I have no proof of this, but it seems a reasonable hunch.)
>
> I don't want to rule this out. Although I'm disputing here that chicken
> resistance actually
> is about burial, maybe there's a way to frame it in that way that would
> make sense to me.
>
> I have not studied so many Condorcet methods that (purport to) be
> chicken-resistant. One
> would probably want a way to measure the characteristics of the method
> (beyond simply
> whether it satisfies the CD criterion or some CD criterion). We might look
> to see reduced
> truncation incentive. The difficulty here is that WV methods have, at face
> value, very low
> truncation incentive, lower than Schwartz//IRV. You may end up with the
> conclusion that
> chicken-resistant methods outperform only in very specific scenarios,
> which would not lead
> me to think there is a connection to an impossibility result.
>
> I note also that I dispute that it was warranted to define the CD
> criterion in such a way
> that IRV or any Condorcet method would satisfy it. I've speculated that
> perhaps DSC comes
> closest to the spirit of it. But DSC plainly encourages burial. I guess it
> makes sense: If
> you're going to penalize truncation then sometimes actual burial (order
> reversal) will be
> the result.
>
> Forest wrote:
> > Our method disappoints the faction X responsible for creating the cycle
> by
> > electing Y, the candidate that the burial or truncation insincerely
> helped
> > (by raising or by truncating below) to create the cycle subverting the
> > sincere CW ... namely Z.
> >
> > The sincerity check will actually elect Z ... but most electorates will
> > think the check is too costly... so they will have to be content to
> > disappoint the faction guilty of creating the insincere cycle ... cycle
> > prevention for future elections.
>
> Part of what I want to point out is that you cannot only disappoint the
> faction that
> truncated. You will also disappoint the faction that did what they were
> supposed to do. And
> both factions have the ability to decide to vote differently in response
> to this potential.
>
> This makes it speculative to believe the effect of chicken resistance is
> less truncation.
> It could as easily be that the effect of chicken resistance is more
> favorite betrayal (or
> fewer candidate nominations by the majority). In either event, will there
> be fewer cycles?
> Sure. Will it be because there are only two candidates in the race?
> Possibly.
>
> From an advocacy standpoint, I am disturbed at how close CD takes us to
> IRV's behavior,
> given that probably the easiest criticism of IRV is its failure to detect
> and take into
> account pairwise majorities. Whatever magic a CD method can do by ignoring
> majorities, IRV
> is already doing - and IRV has no truncation incentive, so it's probably
> doing it more
> reliably.
>
> This isn't to say I don't think the chicken dilemma is a problem. I don't
> want someone to
> read my position as that I don't care about it. It's just that I think
> Mike did not give us
> a plausible remedy.
>
> Kevin
> votingmethods.net
>
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